Vehicles have been equipped with power transfer devices such as transfer cases for many years. Typically, transfer cases allow operation of the vehicle in a two-wheel drive mode or a four-wheel drive mode. Some transfer cases also provide multi-speed functionality.
Over the years, original equipment manufacturers have struggled to provide low cost and energy efficient transfer cases. For example, most transfer cases include wet clutches which exhibit oil churning losses as well as lubrication pump losses. In addition, some actuation systems require a relatively high electrical current draw to activate range and mode shifting systems.
Some of the two-speed transfer cases are relatively complex requiring a large number of relatively expensive components to provide the desired functions. In the past, dedicated single-speed or multi-speed transfer cases either shared few components or a single-speed version occupied the same packaging volume as the multi-speed version. Accordingly, it may be desirable to provide an optimized transfer case having a modular design to meet single-speed or multi-speed applications while maximizing the efficiency of the transfer case by minimizing the energy losses during operation.